package com.hyk.interceptor;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.Maps;
import com.hyk.entity.JwtUser;
import com.hyk.entity.User;
import com.hyk.enums.ApiEnum;
import com.hyk.exception.GlobalException;
import com.hyk.utils.JwtUtils;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;

/**
 * @Author: chen
 * @Date: 2021/3/16 3:37 PM
 * @Version 1.0
 * JWTAuthenticationFilter继承于UsernamePasswordAuthenticationFilter
 * 该拦截器用于获取用户登录的信息，只需创建一个token并调用authenticationManager.authenticate()让spring-security去进行验证就可以了，
 * 不用自己查数据库再对比密码了，这一步交给spring去操作。
 * 这个操作有点像是shiro的subject.login(new UsernamePasswordToken())，验证的事情交给框架。 献上这一部分的代码。
 */
public class JWTAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

    private AuthenticationManager authenticationManager;

    public JWTAuthenticationFilter(AuthenticationManager authenticationManager) {
        this.authenticationManager = authenticationManager;
    }

    @Override
    public Authentication attemptAuthentication(HttpServletRequest request,
                                                HttpServletResponse response) throws AuthenticationException {

        // 从输入流中获取到登录的信息
        try {
            User loginUser = new ObjectMapper().readValue(request.getInputStream(), User.class);
            return authenticationManager.authenticate(
                    new UsernamePasswordAuthenticationToken(loginUser.getUsername(), loginUser.getPassword(), new ArrayList<>())
            );
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    // 成功验证后调用的方法
    // 如果验证成功，就生成token并返回
    @Override
    protected void successfulAuthentication(HttpServletRequest request,
                                            HttpServletResponse response,
                                            FilterChain chain,
                                            Authentication authResult) throws IOException, ServletException {

        // 查看源代码会发现调用getPrincipal()方法会返回一个实现了`UserDetails`接口的对象
        // 所以就是JwtUser啦
        JwtUser jwtUser = (JwtUser) authResult.getPrincipal();
        System.out.println("jwtUser:" + jwtUser.toString());
        Map<String,Object> map = Maps.newHashMap();
        String role = "";
        Collection<? extends GrantedAuthority> authorities = jwtUser.getAuthorities();
        if(authorities == null){
            throw new GlobalException(ApiEnum.USER_NOT_ROLE);
        }
        for (GrantedAuthority authority : jwtUser.getAuthorities()){
            role = authority.getAuthority();
        }
        map.put("role",role);

        map.put("id",jwtUser.getId());
        map.put("username",jwtUser.getUsername());
        String token = JwtUtils.createJWT(jwtUser.getId().toString(),map,jwtUser.getUsername(),3600);
        // 返回创建成功的token
        // 但是这里创建的token只是单纯的token
        // 按照jwt的规定，最后请求的格式应该是 `Bearer token`
        response.setHeader("token", JwtUtils.TOKEN_PREFIX + token);
    }

    // 这是验证失败时候调用的方法
    @Override
    protected void unsuccessfulAuthentication(HttpServletRequest request, HttpServletResponse response, AuthenticationException failed) throws IOException, ServletException {
        response.getWriter().write("authentication failed, reason: " + failed.getMessage());
    }
}